1. Field of the Art
This invention relates to a semiconductor device incorporating a light receiving element or a light-emitting element.
2. Description of the Related Art
The configuration of a conventional optical semiconductor device 100 shall now be described with reference to FIG. 29. FIG. 29A is a plan view of semiconductor device 100 and FIG. 29B is a sectional view of semiconductor device 100.
As shown in FIGS. 29A and 29B, an optical semiconductor element 103 is affixed onto a land 102, formed of copper or other conductive member. Here, a semiconductor element, having a light receiving element, such as a CCD (Charge Coupled Device) image sensor, etc., or a light emitting element, such as an LED (Light Emitting Diode), etc., formed on the top surface thereof, may be employed as optical semiconductor element 103. A plurality of leads 101 are disposed near land 102, and electrodes provided at peripheral parts of optical semiconductor element 103 and leads 101 are electrically connected via metal wires 104.
A transparent resin 105 seals optical semiconductor element 103, land 102, metal wires 104, and leads 101. Transparent resin 105 comprises an optically transparent thermosetting resin or thermoplastic resin. Optical semiconductor element 103 thus performs input and output of optical signals with the exterior via transparent resin 105, which covers its upper part.
However, in order to maintain its transparency, transparent resin 105, which is used in conventional optical semiconductor device 100, does not have a filler added. There is thus a problem in terms of the property of radiating the heat generated from optical semiconductor element 103, and cracks form in transparent resin 105 due to temperature changes under the conditions of use. Transparent resin 105 furthermore has problems in terms of resistance to humidity, mechanical strength, and adhesion to the conductive member. These problems cause optical semiconductor device 100 to be low in reliability.
Also, in order to prevent excessive adhesion of transparent resin 105 to a mold die for performing resin sealing, additives, such as a mold release agent, are mixed in transparent resin 105. The transparency of transparent resin 105 is thus made inadequate due to such additives. Furthermore, since transparent resin 105 itself is a resin, it is poor in transparency in comparison to glass, etc. Thus in the case where optical semiconductor element 103 is a CCD, the performance of the CCD could not be exhibited adequately due to transparent resin 105 attenuating and reflecting the light entering from the exterior.
Also, transparent resin 105 is formed thickly so as to cover not only the top surface of optical semiconductor element 103 but also the peak parts of metal wires 104. The thickness of the entirety of optical semiconductor element 103 is thus increased and there is a limit to making the device compact and thin.
This invention has been made in view of the above problems, and a main object of this invention is to provide a thin optical semiconductor element that is excellent in humidity resistance and mechanical strength and a method of manufacture thereof.